Excellent, thank you! One could mention that vector graphics are in use, but it is great as is.

I would have made it even shorter: inclusive/exclusive and 'required', separated by commas, inside the brackets corresponding to EndX and EndY - but that's just me. Anyway, credits to jsmorley for assessing this and inserting the note there - that's nice to see there are still software where users are listen to, once in a while.

This note will come handy for newcomers in the Rainmeter world or to the Shape meters, as for the already accustomed, it feels natural, since most (if not all) of the meters act pretty much the same way. I only realized that later on, since I was focused on the differences between lines and rectanges in your example, at first.